/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.You may obtain a copy of the License at
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.shenyu.spi;

/**
 * The interface Extension factory.
 * 这是一个服务提供者接口，定义了一个方法 getExtension，用于获取指定类型的扩展实例。
 */
@SPI("spi") // 注解 SPI 是一个标记注解，用于标记一个接口是一个 SPI 接口。在这里，SPI 注解表示这个接口是一个 SPI 接口，并且指定了默认的实现名称为 "spi"
public interface ExtensionFactory {

    /**
     * Gets Extension.
     * 用于获取指定类型的扩展实例
     *
     * @param <T>   the type parameter
     * @param key   the key
     * @param clazz the clazz
     * @return the extenstion
     */
    <T> T getExtension(String key, Class<T> clazz);
}
